Laundry dryers



H. E. HULLAR LAUNDRY DRYERS Jan. 6, 1959 '7 Sheets-Sheet 1 Filed Dec.31, 1952 .aaa

286 @47N VEN TUR HERBERT EHU LLAH TTURNEY Jan. 6, 1959 H. E. HULLAR2,867,430

LAUNDRY DRYERS Filed Deo. 3l, 1952 '7 Sheets-Sheet 2 soa E gg. 3f*

22 26 [NVENTUR HERBERT E. HULLAR www TTURNEY v Jan. 6, 1959 H. E. HULLAR2,867,430

LAUNDRY DRYE-Rs Filed Dec. 3l, 1952 7 Sheets-Sheet 3 INVENTUR HERBERT E.HULLAR TTUPNEY Jan. 6, 1959 H. E. HULLAR 2,867,430

LAUNDRY DRYERS Filed Dec. 31, 1952 7 Sheets-Sheet 5 IN VENTUR HERBERT E.HULLAR BY www TT URNEY Jan. 6, 1959 H. E. HULLAR 2,867,430

LAUNDRY DRYER-S Filed D90. 31, 1952 7 Sheets-Sheet 6 I I l 1 L l 25J/64-8 H NVEEJITURR E RT 254 l RBB ULL ,Sb I BY {CU-VR 25o ATTE/RNE?"Jan. 6, 1959 H.V E. HULLAR 2,867,430

LAUNDRY DRYERS Filed Deo. 3l, 1952 '7 Sheets-Sheet 7 INVENTUR HERBERTBHULLAR ffkww ATT URNEY United g States arent 1 'Claim (Ci. 263-33) Thisinvention relates to laundry. dryers,v and morev particularly to theapplication of radiant energy and heated air to a dryer in an eiiicientmanner, and controls therefor. f

In dryers, Whether gas or-electrically heated, a considerable lamount ofheat is required to evaporate the moisture contained in damp laundry; vThe rate of heat input must be relatively high, in orderAv to avo-id aprotracted drying period. Such heating has in general created a problem,since for .efliciency, the :heat must be caused to be' concentrated uponthe laundry within the drum. At the same time, the heating unitconstitutes a hot spot in a clos'ely-conned cabinet, so that in manydryers, Vthe surrounding cabinet is covered internally with heavy layersof heat insulation to prevent wastage of heat and in an attempt to keepthe cabinet at a suiciently low temperature to be safe. Dryers arelocated in areas where the cabinet is exposed to body contact. Where arectangular cabinet withv a iat top is provided, itl is highlyvdesirable to retainy the top deck sufficiently cool so that it can beused as a work surface.

Accordingly, the present invention is directed toa' dryer having an airand radiant heating unit devised to eiciently convert the heat suppliedto the' drier e'fticiently into hot'air and radiant heat for dryingpurposes. The invention further has to do with thev provision of aheating unit iny which air within the cabinet is utilized asv wardly'directed radiation' in the heating of air entering l the dryer. v

The above and other novel -features ofthe invention will appear morefully hereinafter from the following detailed description when taken inconjunction "with the accompanying drawings. It is-expressly understoodthat the `drawings are employed forpurposes 'of-illustration only, andlare not designed as a denition of thel limitsl of the invention,reference being had for [this purpose .to/60 the appended claims.

11n the drawings, wherein likeI reference characters indicate likeparts: f

Figure l is a front elevationwith parts broken away, showing the drumdrive and front bearings;

Figure2 is la side elevational view taken from within the cabinet sidewall, with parts broken away;

Figurek 3 is a sectional view taken on the line 3--3 of I Figure 2,showing the gasfllred air heater;

Figure 4y is asectional lview taken on the Figure 2, and showing the airpassageglabyi the heater; .f

...maar of mth through' 2 t Figure 5 is a sectional view taken on thebroken section line 5 5 of Figure 4; v

Figure 6 is 'a fragmentary sectional view taken sub@y stantially on theline` 6-6 of Figure l,y showing the lint trap;

Figure 7 is a sectional View taken substantially on the A line 7 7 ofFigure 6';

Figure 8 is a sectional view taken substantially onthe',

line 8-8 of Figure 6;

Figure 9 is a control circuitdiagram; l

Figure 10 ,is atop plan view ofan electric heater" modified form'of theinvention utilizingk a. similarjrair passage labyrinth; and

Fig-ure` ll is asectionalview taken on the line i' of Figure 10.

Referring to Figures l and 2, there isshown a framev I and cabinetstructure, thefr'ame comprising four upright corner angle irons such asare shown at 20,22, and 24, joined together at ythe base -byhorizontally :fore and aft extending angle members as at 26z and front,and'rear cross members as at 28 and 29. 1The front corner angle ironsyare connected by a forwardly disposedchannel l member 30, the ends ofwhich are curved tothe rearas at 3 2 Vfor joining'to' the front faces ofthe corner angle,v

members 22 and 24. The rear corner angle members are joined together bya horizontallyextending channel member 34. The rear .channelmember 34 islocated at a suitable height to .support ,the bearing, while the forwardchannel member 36 is located somewhat below the level of the cabinetdoor. The corner angle irons extend upwardly to a height slightly abovethel channel member 34, vand are conneeted by side channels: 33 'and 35.

A substantially lirriperforate drum 38 having a back wall 40 issupported at the rear upon the channel memf ber 34 throughrfanglemembers such as 42. The drum is provided with -a front, annular member44 having a..

cylindrical forwardly y,extending flangef46 coaxial with the drum. Thedrum is: supported at lthe forward end by means ofginclined. braces 48and', 50, such braces extending from the `channel yrnember'f to thecylindrical llange 46. Within the drum 40 is a perforate laundry-rcontaining cylinder 52, the cylinder having an imper forate, rear will54 to whichy is secured a trunnion 56',

tion within the flange 46 lofthe drum 3.` Within the cylinderSZ are alplurality of fore and aft extending* tumbling ribs or bal-Hes such asy'indicated at 66. The

forward end of they kcylinder S2, and particularly the rim 62, issupported upona pair of rollers 68 and 70, `the roller 70 -beingvrotatably mounted in a fixed Abracket 72 extendingtfrom the cornermember 24, while vthe Vroller 68 isv rotatably mounted in a pivoted'bracket arm 74, such'bracket-arm being pivotally mountedj as at '76 uponthe angle corner member 22. The drum 38 is provided with smallrectangular apertures .such as 7S, through.. which' each of the rollersv68 and 70 project to engage p the rim 62. Y

in order to suppor'tland drive the cylinder-52 by rolling action of therim 62,*orx the rollers 68 and 70, the

roller 68 is a drive roller andis drivenrfrom arnotor 30' throughfriction gearing'comprising'a smallerroller 82 mounted on the forwardendl of:y the motor shaft'81` and. a large cylindrioally faced wheel 84drivably fixed tothe roller shaft 86, which shaftis keyed to thec'ylindersup" EQ@ t PatentedJanfG, `19,59l

The'

seaman f porting roller 68 journalled in the bracket arm 74. Themotoriisrfmounted-in'a U-bracket 88 having motor sup port end arms and92, -which may be of the type shown `in Scheele Patent Nol 2,598,836.VSuch bracket is providedfwith ears'94aand 96 extending to and pivotallymounted upon the bent ends of a Umember 98- y vIt willethus bevseenthat'the height of the lroller`68 mayv be-raised or lowered byadjusting the position of the link 102, so thatthelrollers 68 anrd70.will support the cylinder with its cylindricall` flange 65 in coaxialrelation tothe cylindrical flange 46 ofthe surrounding drum. The rearbearing 36, tlrrugift-*heI resilient mountv A6,0, provides. slightuniversalmovmeiit in supportingthe rearof the cylinder,

so that/the weight of the'forward end of the cylinder restsupontherollers 68-and 70, and particularly with suicient-weight on theroller 68 to assure a satisfactory v drive, roller 68-being locatedlower than roller 70, so'as 'to carry a greater proportion of theweight. Rotation is the direction of arrow A or counterclockwise, asviewed in Figure 1.

e The drum 38 is provided on the upper side thereof to one side ofcenter with an enlarged rectangular air inlet aperture V over whichthere is positioned a heater unit generally indicated as at 112 (seeFigures 3 and 4, for example), Which heater unit may be provided with acurved saddle-like plate 114 adapted 'to be secured to the drum alongit's upper edge vby screw fastening means 116, such saddle plate beingof arcuate form and being adapted to cover the enlarged rectangularaperture 110. Air is admitted to the drum'through the aperture 110 afterbeing suitably heated by agas burner which will be hereinafter describedin more detail. The ldrum structure, however, Iis adapted to receive anelectrical heater, as an alternative, which heater will be alsohereinafter described in more detail in connection with'Figures 10 yandlfl.4 Ist should be understood that the two forms of heaters are l soconstructed as to be interchangeable insofar as thel drum is concerned,

i Air withdrawn from 'the drum38 through a lower duct 118V locatedslightlyto lthe rear and y'diagonally opposite z the inlet. Such duct isrigidly secured to the drum by a j flange 120 and extends downwardly toapoint substantially in alignment'withftheshaft of the motor 80. The'duct has a front llat face`122 having a circular aperture 124 insubstantial alignment with the shaft 81 of the motor 80. Between theduct 118 and the rear of the motor, there is positioned a centrifugalblower 126 hav.- ing the usual impeller 128 therein. The blower has aninvolute housing wall 130 discharging into an outlet duct 132-directeddownwardly at approximately a 45 angle toward the lower central regionbeneath the drum of the dryer.

iSuch discharge duct connects v`with a lint trap 134 generallyillustrated in Figures 6-8. The trap comprises a rectangularhousinghaving top and bottom members 136 and 138, side walls 140 and 142, and arear end wall 144. The discharge duct 132 connects with an angularlydisposed lint trap inlet connection 146 extending angularly from onecorner of the housing formed by the top and s side walls 136 and 140.Such inlet connectionl is located adjacentitherear wall 144. Withinthecasing, there isprovided a drawer-likescreen. assembly.` The screen isformed to providey acentral inclined planar portion 148, a narrowinclined planar side portion 150, and a wide inclined planar sideportion 152.V The screen is braced at the rearby a strut 154connectingthe ysides 150 and 152. The, forward edge of the screen issecured t0 .4 front panel 156, having a forward extending ,ledge 158provided with a drawer pull formedby the'forward edge of the ledge 158being bent upwardly and rearwardly as shown in Figure 8. The front panel156 is provided with a rectangular exhaust aperture 162, such aperturebeing located within and below-the line of attachment of the screen 148with the front. panel. The upper planar portion of the screen isconstructed somewhat more narn row to the rear thereof, so as to providea tapered distributing zone 164 to'facilitate distribution along theilength of the screen ofair entering through the rearinclined connection146. It will be seen that thescreen intercepts air entering through the-inlet connection 146 prior toits leaving the lint box through'the frontaperture 162. vIf it be desired. to `eolnnectlthejv lint box to anexhaust port or duct such as isindicated at 166, the side wall 142 maybe provided with a slide plate 168 which may be removedv for thatpurpose. In such case, theoutlet duct 166wi1l1`ead"fronrfthspace'belirid the inclined plananscreen portion152.-'l ,-,Itffwill'be "sen'lthat'the'fpbr; s tions ofthe screen`^152and"148"arig'ularly' connect alorglgv a fold which extends rearwardlyimmediately: be-I neath the top wall '136' to prevent bypassing', sothat in leaving the lint box' through outlet duct 166, must firsttraverse the area of the screen portions 148 or v150 and thereafter theareaof the screen portion 152. The

lint box is supportedatvv its forward end upon the ltransverse framemember 28 through tabs 151 and a'clip member I 153, andthe inletconnection 146 is coupled to the`- discharge duct 132 by a resilientannular cuff 1172.

The front wall 129 ofthe blower 126 is supported from i face 133 vof theblower and the-front wall 122 of thev duct 118 tok couple the aperturev124 with-the blower.4

Thus, it will be seen that the blower inletand outlet connections,through lthe ring 174 and .cuff 172, areinsulated against thetransmission lof vibration from the motor and blower to the drum andlint box. Y Y

In order to supply hot air to.` the drum 38, there :is mounted'upon thesaddle plate 114 a gas burner 176 anda housing 178 therefor havingsuitable ducts for" e'ciently heating air for admission to the drum 38.vTheV housing comprises end members or walls 180 and 182 mountedwbyflanges 184 and Y186. u'pon the saddle plate `114. 'lhev end membersvarejoined by anouter wall or J shell or lcover 188 having anzinclined topVsurface portion 190 and a vertically extending. ,port ion.19 2f. lWithinthe housing are bales 194 and' l196-,":thel baffle 194v extendingparallel and in spaced relation withtheinclined; top or lateral portion190;to ;a point 198 spaced from the vertical wall portion 192.Suchgbaflle has a curved forward portion 200 extending somewhat radiallyto the saddle member 114. The rbaille 194 extends from either end wall180 and 182, andis suitable secured to the end walls and sad- 'dlemember by anges 202, 204 and 206. The baffle 196 is provided with acentral portion 208 extending in spaced parallel relation to the baille194. The lower end por,

tion lcontinues in a'downwardly extending position` 210 extending inspaced parallel relation to the outer wall portion 192. The upper endextends downwardly'or sonre-4 whatradially. as at 212 toward the saddlemember 114.

The baille 196 extends from end wall 180 to end wall 182, i

and is suitably secured tosuch end `walls vby anges 214, 216 and 218.The saddlevmember, 114 is provided with an elongated rectangularaperture 220, a portion of which aperture connects with the spacebetween the end portions 212 and 200 of the bales 194 and 19,6, aswellas the space beneath Vthe baflle196. The burner 176 is lo.-

cated between the lower'portio'n of thesaddle member 114 and the outerwall 192 of lthe shell 188 and beneath the inner baille 196.

It will be seen that by reason of the burner, air''ntering at 222 willrncve upwardly joining the burned gases, and enter the drum through thelower portion of the aperture 220. Air will also pass through thepassage-- shell outer wall 190. Such air thereafter passes into the endspace 230 adjacent the end 198 of the baille 194, thereafter llowsthrough the space 232 between the baffles 194 and 196 to enter the drumthrough the opening 220. It will thus be seen that cool air entering at226 and passing through the space 228 tends to absorb the heat of thegas burner and forms an ever-changing insulating layer of cool air,having a highly beneficial effect in retaining the outside dryer cabinetcomparatively cool. In addition, the double pass for air entering thedrum formed by the space 228 and the space 232, provides a highlyefficient air heater, so that economy in the consumption of gas results.The channel 224 likewise is cooled by entering air, which air joins thatentering at 226.

The gas burner projects into the space between the outer housing portion192 and the saddle plate 114, and extends substantially the entirelength of the housing 178, the burner proper comprising a series of jets234 arranged in double rows 236 and 238. The jets are formed by aU-stamping 235, and two spaced stampings 237 and 239, the latter alsoforming a lengthwise manifold 241 connected by a conduit 243 leading tothe usual air valve 245. The burner is supported by a rear plate 247extending into a slit in the rear wall 182, and by a bracket 249 at theforward end secured to the front wall as at 251. A baille plate 240 ismounted upon the burner and extends the length thereof, such baillebeing adapted to prevent air flow from disturbing the gas llame. Thesaddle plate 114 is provided with a turned-up flange 115 along its lowermargin, which cooperates with the burner parts 237 and 239, andparticularly the web 117, so as to prevent cold air from enteringbetween the burner and drum. The end wall 182 has an inspection aperture242 located above the end of the burner, the inspection opening beingformed by a struck-out portion of metal 244, such portion being bentoutwardly from the wall 182 and adapted to carry a thermostatic switch246.

It will be seen that the saddle plate 114, being exposed to the radiantheat of the llame of the burner 176, will become heated and provide initself a source of radiant heat, the inner surface of such plate beingexposed to the perforate cylinder within the drum 38 by reason of therelatively large aperture 110 in the drum, which aperture is effectivelycovered by the arcuate saddle member 114.

The burner also includes, mounted on a bracket 251 and arm 47', theusual pilot burner 248, a hot wire starter 250, and a draft shield 252,all of which project through a window 181 in the end wall 180. TheWindow 181 is aligned with an inspection opening 133 in the front wall282 of the cabinet. A thermostatic bulb 254 is located adjacent thepilot burner 248. Gas is supplied to the main burner through a pipe 256extending to a solenoid valve component 258 and a gas supply pipe 260,the latter having a stop cock 262 and pressure regulator 264. Thesolenoid valve 258 also includes a solenoid valve for the pilot, therebeing provided a separate pipe 266 leading from the valve 258 to thepilot 248.

The drum is provided with a sterilizer lamp 268 and a lamp 270 forillumination connected in series therewith, such lamps being housed in acasing 272 mounted on the upper side of the drum, the drum beingprovided with an aperture (not shown) substantially coextensive with andcovered by the housing 272. A temperature- 6 sensitive thermostaticswitch 274 is located in the top of the drum and a temperature-sensitivebulb 276 is located in the air duct 118 leading from the drum to theblower.

Surrounding the frame and drum is a cabinet structure having side walls27S and 280, a front wall composed of a door frame member 282, and akick plate 284, the latter having a re-entrant lower portion 286 forminga `drawer frame for the cover panel 156 of the drawerlike screenassembly of the lint box. The door frame member 282 has a rectangularinwardly offset frame proper 288, having a circular aperture 290 adaptedto join with the flange 46 through an annular resilient gasket 292. Adoor 294 is hinged to the door frame proper as at 296, such door havinga window 298 and handle 300. The door, when closed actuates a doublethrow switch 302, closing one circuit and opening another as the door isclosed or opened. The cabinet is further composed of a back plate 304and a top deck 306 having a rearwardly upswept inclined control panel308, behind which is mounted a master switch 310 manually actuated by astarting and temperature setting knob 312 and a start push button 314.

Control of the drier is effected through a circuit diagrammaticallyshown in Figure 9, utilizing a temperature control thermostatic switchdevice such as shown in Patent No. 2,564,868, issued August 21, 1951.The manual start and temperature selector knob 312 is adapted toinitially close the pairs of switch contacts 316 and 318, and thereaftereffect an adjustment upon the thermostatic bellows 320, which bellowsare actuated by the bulb 276. By varying the pressure upon such bellows,the temperature at which the gas burner will be shut off can be variedto accommodate different types of laundry loads, as will hereinafterappear. The start push button 314, when depressed, is adapted to closeand hold closed three circuits by bridging contacts 322 and 324,bridging contacts 326 and 323, and by bridging contacts 33t) and 332.'Thus, if the pairs of contacts 316 and 318 are closed and the push startswitch is depressed to bridge the contacts operated thereby, a circuitis established from line wire 334 through lead 336 to lead 338, andthrough door switch 302 and contact 341 to the motor through the lead342 and the return lead 344 connected to the line wire 346. Thus, whenthe door is closed, the motor will start. At the same time, the line 346is connected through bridged contacts 322 and 324 to the thermostaticswitch line 348 having arranged in series therein the thermostaticswitch 246 and thermostatic switch 274, such line leading to the gasvalve component` 258 and more particularly to the pilot light contacts350 and 352 contained therein. The pilot igniter component 277,sometimes referred to as a Warp switch, contains a circuit that isenergized through contacts 350 and 352 when closed, and also by acircuit established by bridging contacts 326 and 328, a centrifugalswitch 354 in the motor 80, such centrifugal switch being in the circuit356 leading to the pilot igniter. The centrifugal motor switch isnecessarily electrically insulated from the usual induction motorstarting switch, since the circuit is broken when the motor is stopped.Such switch may be operated by the same centrifugally responsive meansutilized for opening the induction motor starting switch when sufficientrotation speed has been attained.

It will be seen that the primary coil 358 of the pilot ignitertransformer 359 will be energized by current flowing from the closedcontacts 350 and 352 and current supplied through the line 356 throughthe centrifugal switch 354, such current passing through the contacts360 andV 362, su'ch contacts being normally closed initially, but beingopened after a brief fixed period of time by reason of the contact 360being mounted on a bimetallic heat-sensitive leaf heated by theresistance 364. The heat of such resistance acts to open the contactsafter a predetermined period. When the primary 35S 7 of the pilotigniter coil transformer is energized, the secondary 366 connected tothe hot wire 250 renders such wire incandescent and effective to ignitethe pilot.

It will also appear that the pilot valve operating solenoid 368 isconnected at this time across the primary 358 of the pilot ignitertransformer, so that the pilot valve supplying gas to the pilot burner248 is opened. When the pilot burner ignites, the bulb 254 becomesheated and acts in response to temperature rise to open contacts 350 and352 and close contacts 351 and 353, thus closing a circuit through themain gas valve solenoid 370. When the contacts 350 and 352 open, theprimary 358 of the ignition transformer is deenergized, while the pilotvalve solenoid continues to be energized from line 348 and throughcontacts 360 and 362, leading to the centrifugal 1 switch 354 throughlead 356, the pilot valve remaining open until the time period for theopening of contacts 360 and 362 has elapsed, such contacts breaking thecircuit to the pilot valve.

The push start switch 314, when actuated, is locked with the contactsbridged until actuated by the bellows 320 in response to temperaturerise in the outlet duct 118. y

by bridging contacts 330 and 332 through the bridging bar 333, whichmaintains a circuit through the motor 80 as may be traced by followinglead 336, bar 333, lead 338, door switch 302, lead 342, and lead 344.The motor will thereby continue to run until such time as thethermostatic bellows 320 cools suiciently to open the contacts 330 and332.

The door switch is provided with a door open contact 372 which isconnected to the line 334 through a lead 374. When the door switch isopened, the germacidal lamp and the illuminating lamp are energizedthrough the lead 344. This circuit is completed irrespective of whetherline contacts 316 and 318 are closed or open.

The resistance 364 is adapted to open the contacts 360 and 362, after aperiod of four minutes or so, while if the pilot ignites immediately, aswould be normal operation, the contacts 350 and 352 are opened, and thecontacts 351 and 353 closed within a minute, the time taken for the bulb254 to be heated by the pilot. contacts 360 and 362 remain closed, andboth pilot and main burner remain lighted during normal operation. Suchburners are setto provide the necessary steady heat t0 effect drying solong as the normal flow of air through the drum takes place.

Should the lint trap become clogged, choking olf the flow, thetemperature will rise above that set for thermostats 246 orV 274, orboth, causing circuit 348 to be opened at one or the other thermostat.This shuts o the main gas valve, until the circuit 348 is restored. Ahigh resistance signal lamp 382, bridging either one or preferably boththermostats 246 and 274, will serve to indicate such a condition, andmay be provided with a trans- Thus, r

lucent sign illuminated by the lamp reading Clean lint In a short time,thermostat 254 cools sufficiently to open A contacts 351 and 353 to openthe circuit to solenoid valve f 370, cutting ohc the main burner. Y Whenthe motor is running and the door is in closed position, it will be seenthat the germicidal lamp and illuminating lamp are connected across themotor 80, so that such lamps are energizedat all times that the motor isrunning. When the door is opened, causing the motor to stop,.thecentrifugal switch 354 opens, cutting off both pilot and main burner gassupplies. -It will of course be appreciated that the motor does not slowdown instantly, so that if the door is opened for a brief instant notlong enough to slow the motor to lopen the centrifugal switch contacts354, the burners will continue. Cutting ot the burners when the cylinderis stopped .aifords safety against overheating, since with a stoppedmotor, circulation is cut olf, as well as tumbling.

In Figures 10 and 1l, there is shown an electrical heating unit whichmay be applied to the drum, the same form-- ing a unit which can besubstituted for the gas burner air heater with no structural change tothe drum. There is shown :a shell 400 having an outer wall 402 withintegral top and bottom walls 404 and 406 and end walls 408 and 410. Theshell is of suflicient size to cover the aperture 110 in the drum 38.The shell is adapted to close the aperture 110 and the top wall isprovided with a flange Y 412 adapted to seat upon the drum adjacent theaperture and be secured to the drum by screws 116. The shell 400 and thesaddle member 114 are both adapted to be secured to the drum along thelower edge by an' S-sectioned clip member 414 which is equally adapted.

to engage the ange 413 along the bottom wall edge or the lower edge ofthe saddle plate 114. n

Within the shell 400 is a bale plate 416 substantially uniformly spacedfrom the outer shell wall 402, such baille extending from end wall toend wall and being curved at the lower end as at 418 and terminating asat 420 a short distance from the lower or bottom Wall 406. The upper endof the baie 416 is bent as at 422 and the end 424 thereof is joined tothe top wall 404. A portion 426 of the shell outer or top Wall 402 iscut away to provide an inlet, the same being bent into parallel relationwith the portion 422 of the bale 416. The balfle 416 is provided with aplurality of narrow slits 428 which permit some of the air entering theshell to flow radially inward with respect to the drum, while theremainder travels the length of the space between the bafe and shell,passing through the space between the bottom wall 406 and lower edge420. Air entering through the slits 428 traverses the electricalinfrared heating grid 430 supported within the shell beneath the bale416. Such grid comprises a plurality of heater coils 432 so disposed ast0 transmit radiant energy to the perforate cylinder within the drum aswell as to the baille 416, whereby the heating unit acts both to heatlair passing behind the baffle as well as to provide radiant heatdirected toward the cylinder in a fashion similar to the gas burnerheated saddle plate of the gas burner modification. The resistanceheating unit is supported at one end on an end terminal plate 434mounted on the end wall 410, such plate having electrical terminals 436extending therethrough. The grid also carries lugs 438 at the other end,which are projected through the end wall 408 for support.

Reference has heretofore been made to Patent No. 2,565,868, as showing atemperature control thermostatic switch device similar to thatdiagrammatically included in Figure 9. When an electrical heating unitis employed, they circuit shown in said patent may be employed.

It will be seen that in the modifications utilizing either gas orelectricity, there is provided an air insulating blanket between thesource of heat and the outside A cabinet. The air blanket in each caseconsists of a layer of constantly changing cool air entering the shellaround Vthe source of heat, which air after entrance, is graduallyheated by the gas burner or electrical unit, as the case w may be. Thecold air, however, in entering through the blanket passageway, rendersthe heating unit in either case highly efficient and prevents escape `ofheat by radiation or otherwise to the surrounding cabinet walls, so thatsuch cabinet remains cool and may be safely used for work space. By suchan arrangement, expensive layers of insulating material upon the innersurface of the cabinet walls may be dispensed with, because the heat isabsorbed by the entering cool air and drawn into the drum to effect theevaporation of moisture therein contained in the laundry being dried.

While several modifications of the invention have been illustrated anddescribed, it is to be understood that the invention is not limitedthereto. As various changes in the construction and arrangement may bemade without departing from the spirit of the invention, as will be apparent to those skilled in the art, reference will be had to theappended claims for a definition of the limits of the invention.

What is claimed is:

A laundry dryer comprising a substantially imperforate drum arrangedwith its axis substantially horizontal, a laundry tumbling cylinderrotatably mounted therein having a perforate peripheral wall, asubstantially rectangular cabinet surrounding said drum, said drumhaving a large aperture in an upper side wall thereof facing an uppercorner of said cabinet formed by a side wall and the top thereof, meansfor withdrawing air from said drum at a point remote from said aperture,an arcuate plate adapted to be attached to said drum in coveringrelation to said drum aperture, axially spaced end Walls mounted on saidplate and a cover connecting said end walls and spaced radially outwardof said plate and having a ver tical portion and a lateral extendingportion, said cover and curved plate forming a circumferentially openended box, a burner in the space between said plate and cover adjacentthe lower end, inner and outer spaced bafes arranged within said box andextending between said ends and in substantially parallel relation tothe lateral portion of said cover, said outer baille being nearest saidcover,

f the outer bale underlying substantially the lateral portion of saidcover, and the inner bafe underlying said first named baffle and havinga portion extending downwardly along and in spaced relation to thevertical portion of said cover lto a point below the upper portion ofsaid burner and between said burner and cover, said baies at their upperend having portions extending substantially radially toward said drumand to said plate, said radial portions being circumferentially spaced,said plate having an aperture bounded at opposite ends substantially bysaid end walls, and along its upper edge by the radial portion of saidouter plate, and having its lower edge below the radial portion of saidinner baflie, whereby to provide an air inlet path to said drum from theupper open end of said cover downwardly between said cover and outerbaflie, and upwardly between said bafe to said aperture, a secondpassage extending upwardly between said cover and inner batlie andjoining the path between said bafes leading to said plate aperture, anda third path following underneath said inner baffle to the lower portionof said plate aperture.

References Cited in the tile of this patent UNITED STATES PATENTS2,193,889 Sliger Mar. 19, 1940 2,398,880 Broglie Apr. 23, 1946 2,460,422Koppel Feb. 1, 1949 2,506,517 Moore May 2, 1950 2,548,313 Kauffman Apr.10, 1951 2,564,867 Weber et al. Aug. 21, 1951 2,590,808 Wagner Mar. 25,1952 2,599,623 Forrester June 10, 1952 2,664,646 Bourner Jan. 5, 19542,690,905 Smith Oct. 5, 1954

